dolly (n.)youdaoicibaDictYouDict[dolly 词源字典]
c. 1600, Dolly, a fem. nickname (see doll); 1790 as "child's doll;" applied from 1792 to any contrivance fancied to resemble a dolly in some sense, especially "a small platform on rollers" (1901). Doesn't look like one to me, either, but that's what they say.[dolly etymology, dolly origin, 英语词源]